Methods Used to Study the Brain

Many different methods are used to study brain functions. They include the following:

The oldest evidence for this idea comes from the effects of brain damage. Brain damage disrupts
different psychological processes, depending on where brain damage is, when it occurred, how it
occurs, etc. No psychological process seems immune.

More recently, researchers and clinicians (people who treat patients) have showed that electrical
stimulation at different places in the brain also selectively affects specific psychological processes,
depending on where the stimulation is.

Chemical stimulation in the form of psychologically active medications and recreational drugs also
selectively affects mental processes. Antipsychotic medications, anesthetics and analgesics, antianxiety
medications, nicotine in tobacco, cocaine, heroin, hallucinogens, like LSD, etc. all produce their different
effects because the act on specific different brain systems.

Recording the electrical signals from the brain from electrodes pasted to the
scalp or (usually in animals) electrodes in the brain itself shows different patterns of activity associated
with different mental processes.

Most recently and dramatically, more or less direct measurements using various computer-based
imaging technologies (scans using PET, fMRI, CAT, etc) show that different parts of the brain are
activated during different psychological actions. These imaging methods allow the study of brain
structure and function in normal healthy volunteers as well as people with diseases of the brain (or other
parts of the body), because they involve no invasion into the body.